The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path icmp_route_lookup() performs multiple route     lookups to find a suitable route for sending ICMP error messages, with special handling for XFRM (IPsec)     policies. The lookup sequence is: 1. First, lookup output route for ICMP reply (dst = original src) 2.
    Pass through xfrm_lookup() for policy check 3. If blocked (-EPERM) or dst is not local, enter reverse     path 4. In reverse path, call xfrm_decode_session_reverse() to get fl4_dec which reverses the original     packet's flow (saddr<->daddr swapped) 5. If fl4_dec.saddr is local (we are the original destination), use
    __ip_route_output_key() for output route lookup 6. If fl4_dec.saddr is NOT local (we are a forwarding     node), use ip_route_input() to simulate the reverse packet's input path 7. Finally, pass rt2 through     xfrm_lookup() with XFRM_LOOKUP_ICMP flag The bug occurs in step 6: ip_route_input() is called with     fl4_dec.daddr (original packet's source) as destination. If this address becomes local between the initial     check and ip_route_input() call (e.g., due to concurrent ip addr add), ip_route_input() returns a LOCAL     route with dst.output set to ip_rt_bug. This route is then used for ICMP output, causing dst_output() to     call ip_rt_bug(), triggering a WARN_ON: ------------[ cut here ]------------ WARNING:
    net/ipv4/route.c:1275 at ip_rt_bug+0x21/0x30, CPU#1 Call Trace: <TASK> ip_push_pending_frames+0x202/0x240     icmp_push_reply+0x30d/0x430 __icmp_send+0x1149/0x24f0 ip_options_compile+0xa2/0xd0     ip_rcv_finish_core+0x829/0x1950 ip_rcv+0x2d7/0x420 __netif_receive_skb_one_core+0x185/0x1f0     netif_receive_skb+0x90/0x450 tun_get_user+0x3413/0x3fb0 tun_chr_write_iter+0xe4/0x220 ... Fix this by     checking rt2->rt_type after ip_route_input(). If it's RTN_LOCAL, the route cannot be used for output, so     treat it as an error. The reproducer requires kernel modification to widen the race window, making it     unsuitable as a selftest. It is available at:
    https://gist.github.com/mrpre/eae853b72ac6a750f5d45d64ddac1e81 (CVE-2026-45905)

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Linux Distros Unpatched Vulnerability : CVE-2026-45905

medium Nessus Plugin ID 317242

Version 1.2